SPDY client example

Demonstrates the usage of SPDY from a client perspective. One can also
use a SPDY-enabled browser as a client, but it’s easier to understand
the internals of the protocol from a client point-of-view if you have
some code you can debug.

example/src/main/java/io/netty/example/spdyclient/HttpResponseClientHandler.java

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+/*
+ * Copyright 2014 The Netty Project
+ *
+ * The Netty Project licenses this file to you under the Apache License,
+ * version 2.0 (the "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at:
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ */
+package io.netty.example.spdyclient;
+
+import io.netty.channel.ChannelFuture;
+import io.netty.channel.ChannelHandlerContext;
+import io.netty.channel.SimpleChannelInboundHandler;
+import io.netty.example.http.snoop.HttpSnoopClientHandler;
+import io.netty.handler.codec.http.HttpContent;
+import io.netty.handler.codec.http.HttpHeaders;
+import io.netty.handler.codec.http.HttpObject;
+import io.netty.handler.codec.http.HttpResponse;
+import io.netty.handler.codec.http.LastHttpContent;
+import io.netty.util.CharsetUtil;
+
+import java.util.concurrent.BlockingQueue;
+import java.util.concurrent.LinkedBlockingQueue;
+
+/**
+ * This is a modified version of {@link HttpSnoopClientHandler} that uses a {@link BlockingQueue} to wait until an
+ * HTTPResponse is received.
+ */
+public class HttpResponseClientHandler extends SimpleChannelInboundHandler<HttpObject> {
+
+    private final BlockingQueue<ChannelFuture> queue = new LinkedBlockingQueue<ChannelFuture>();
+
+    @Override
+    public void messageReceived(ChannelHandlerContext ctx, HttpObject msg) throws Exception {
+        if (msg instanceof HttpResponse) {
+            HttpResponse response = (HttpResponse) msg;
+
+            System.out.println("STATUS: " + response.getStatus());
+            System.out.println("VERSION: " + response.getProtocolVersion());
+            System.out.println();
+
+            if (!response.headers().isEmpty()) {
+                for (String name : response.headers().names()) {
+                    for (String value : response.headers().getAll(name)) {
+                        System.out.println("HEADER: " + name + " = " + value);
+                    }
+                }
+                System.out.println();
+            }
+
+            if (HttpHeaders.isTransferEncodingChunked(response)) {
+                System.out.println("CHUNKED CONTENT {");
+            } else {
+                System.out.println("CONTENT {");
+            }
+        }
+        if (msg instanceof HttpContent) {
+            HttpContent content = (HttpContent) msg;
+
+            System.out.print(content.content().toString(CharsetUtil.UTF_8));
+            System.out.flush();
+
+            if (content instanceof LastHttpContent) {
+                System.out.println("} END OF CONTENT");
+                this.queue.add(ctx.channel().newSucceededFuture());
+            }
+        }
+    }
+
+    @Override
+    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
+        this.queue.add(ctx.channel().newFailedFuture(cause));
+        cause.printStackTrace();
+        ctx.close();
+    }
+
+    public BlockingQueue<ChannelFuture> queue() {
+        return this.queue;
+    }
+
+}

example/src/main/java/io/netty/example/spdyclient/SpdyClient.java

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+/*
+ * Copyright 2014 The Netty Project
+ *
+ * The Netty Project licenses this file to you under the Apache License,
+ * version 2.0 (the "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at:
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ */
+package io.netty.example.spdyclient;
+
+import static java.util.concurrent.TimeUnit.SECONDS;
+import io.netty.bootstrap.Bootstrap;
+import io.netty.channel.Channel;
+import io.netty.channel.ChannelFuture;
+import io.netty.channel.ChannelOption;
+import io.netty.channel.EventLoopGroup;
+import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.socket.nio.NioSocketChannel;
+import io.netty.handler.codec.http.DefaultFullHttpRequest;
+import io.netty.handler.codec.http.HttpHeaders;
+import io.netty.handler.codec.http.HttpMethod;
+import io.netty.handler.codec.http.HttpRequest;
+import io.netty.handler.codec.http.HttpVersion;
+
+import java.net.InetSocketAddress;
+import java.util.concurrent.BlockingQueue;
+
+/**
+ * An SPDY client that allows you to send HTTP GET to a SPDY server.
+ * <p>
+ * This class must be run with the JVM parameter: {@code java -Xbootclasspath/p:<path_to_npn_boot_jar> ...}. The
+ * "path_to_npn_boot_jar" is the path on the file system for the NPN Boot Jar file which can be downloaded from Maven at
+ * coordinates org.mortbay.jetty.npn:npn-boot. Different versions applies to different OpenJDK versions. See
+ * {@link http://www.eclipse.org/jetty/documentation/current/npn-chapter.html Jetty docs} for more information.
+ * <p>
+ */
+public class SpdyClient {
+
+    private final String host;
+    private final int port;
+    private final HttpResponseClientHandler httpResponseHandler;
+    private Channel channel;
+    private EventLoopGroup workerGroup;
+
+    public SpdyClient(String host, int port) {
+        this.host = host;
+        this.port = port;
+        this.httpResponseHandler = new HttpResponseClientHandler();
+    }
+
+    public void start() {
+        if (this.channel != null) {
+            System.out.println("Already running!");
+            return;
+        }
+
+        this.workerGroup = new NioEventLoopGroup();
+
+        Bootstrap b = new Bootstrap();
+        b.group(workerGroup);
+        b.channel(NioSocketChannel.class);
+        b.option(ChannelOption.SO_KEEPALIVE, true);
+        b.remoteAddress(new InetSocketAddress(this.host, this.port));
+        b.handler(new SpdyClientInitializer(this.httpResponseHandler));
+
+        // Start the client.
+        this.channel = b.connect().syncUninterruptibly().channel();
+        System.out.println("Connected to [" + this.host + ":" + this.port + "]");
+    }
+
+    public void stop() {
+        try {
+            // Wait until the connection is closed.
+            this.channel.close().syncUninterruptibly();
+        } finally {
+            if (this.workerGroup != null) {
+                this.workerGroup.shutdownGracefully();
+            }
+        }
+    }
+
+    public ChannelFuture send(HttpRequest request) {
+        // Sends the HTTP request.
+        return this.channel.writeAndFlush(request);
+    }
+
+    public HttpRequest get() {
+        HttpRequest request = new DefaultFullHttpRequest(HttpVersion.HTTP_1_1, HttpMethod.GET, "");
+        request.headers().set(HttpHeaders.Names.HOST, this.host);
+        request.headers().set(HttpHeaders.Names.ACCEPT_ENCODING, HttpHeaders.Values.GZIP);
+        return request;
+    }
+
+    public BlockingQueue<ChannelFuture> httpResponseQueue() {
+        return this.httpResponseHandler.queue();
+    }
+
+    public static void main(String[] args) throws Exception {
+        int port;
+        if (args.length > 0) {
+            port = Integer.parseInt(args[0]);
+        } else {
+            port = 8443;
+        }
+
+        final SpdyClient client = new SpdyClient("localhost", port);
+
+        try {
+            client.start();
+            ChannelFuture requestFuture = client.send(client.get()).sync();
+
+            if (!requestFuture.isSuccess()) {
+                requestFuture.cause().printStackTrace();
+            }
+
+            // Waits for the complete HTTP response
+            ChannelFuture responseFuture = client.httpResponseQueue().poll(5, SECONDS);
+
+            if (!responseFuture.isSuccess()) {
+                responseFuture.cause().printStackTrace();
+            }
+
+            System.out.println("Finished SPDY HTTP GET");
+        } finally {
+            client.stop();
+        }
+    }
+}

example/src/main/java/io/netty/example/spdyclient/SpdyClientInitializer.java

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+/*
+ * Copyright 2014 The Netty Project
+ *
+ * The Netty Project licenses this file to you under the Apache License,
+ * version 2.0 (the "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at:
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ */
+package io.netty.example.spdyclient;
+
+import static io.netty.handler.codec.spdy.SpdyVersion.SPDY_3_1;
+import static io.netty.util.internal.logging.InternalLogLevel.INFO;
+import io.netty.channel.ChannelInitializer;
+import io.netty.channel.ChannelPipeline;
+import io.netty.channel.socket.SocketChannel;
+import io.netty.example.securechat.SecureChatSslContextFactory;
+import io.netty.handler.codec.spdy.SpdyFrameDecoder;
+import io.netty.handler.codec.spdy.SpdyFrameEncoder;
+import io.netty.handler.codec.spdy.SpdyHttpDecoder;
+import io.netty.handler.codec.spdy.SpdyHttpEncoder;
+import io.netty.handler.codec.spdy.SpdySessionHandler;
+import io.netty.handler.ssl.SslHandler;
+
+import javax.net.ssl.SSLEngine;
+
+import org.eclipse.jetty.npn.NextProtoNego;
+
+public class SpdyClientInitializer extends ChannelInitializer<SocketChannel> {
+
+    private final HttpResponseClientHandler httpResponseHandler;
+
+    public SpdyClientInitializer(HttpResponseClientHandler httpResponseHandler) {
+        this.httpResponseHandler = httpResponseHandler;
+    }
+
+    private static final int MAX_SPDY_CONTENT_LENGTH = 1024 * 1024; // 1 MB
+
+    @Override
+    public void initChannel(SocketChannel ch) throws Exception {
+        SSLEngine engine = SecureChatSslContextFactory.getClientContext().createSSLEngine();
+        engine.setUseClientMode(true);
+        NextProtoNego.put(engine, new SpdyClientProvider());
+        NextProtoNego.debug = true;
+
+        ChannelPipeline pipeline = ch.pipeline();
+
+        pipeline.addLast("ssl", new SslHandler(engine));
+        pipeline.addLast("spdyEncoder", new SpdyFrameEncoder(SPDY_3_1));
+        pipeline.addLast("spdyDecoder", new SpdyFrameDecoder(SPDY_3_1));
+        pipeline.addLast("spdyFrameLogger", new SpdyFrameLogger(INFO));
+        pipeline.addLast("spdySessionHandler", new SpdySessionHandler(SPDY_3_1, false));
+        pipeline.addLast("spdyHttpEncoder", new SpdyHttpEncoder(SPDY_3_1));
+        pipeline.addLast("spdyHttpDecoder", new SpdyHttpDecoder(SPDY_3_1, MAX_SPDY_CONTENT_LENGTH));
+        pipeline.addLast("spdyStreamIdHandler", new SpdyClientStreamIdHandler());
+        pipeline.addLast("httpHandler", httpResponseHandler);
+    }
+}

example/src/main/java/io/netty/example/spdyclient/SpdyClientProvider.java

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+/*
+ * Copyright 2014 The Netty Project
+ *
+ * The Netty Project licenses this file to you under the Apache License,
+ * version 2.0 (the "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at:
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ */
+package io.netty.example.spdyclient;
+
+import static io.netty.handler.codec.spdy.SpdyOrHttpChooser.SelectedProtocol.HTTP_1_1;
+import static io.netty.handler.codec.spdy.SpdyOrHttpChooser.SelectedProtocol.SPDY_3_1;
+
+import java.util.List;
+
+import org.eclipse.jetty.npn.NextProtoNego.ClientProvider;
+
+/**
+ * The Jetty project provides an implementation of the Transport Layer Security (TLS) extension for Next Protocol
+ * Negotiation (NPN) for OpenJDK 7 or greater. NPN allows the application layer to negotiate which protocol to use
+ * over the secure connection.
+ * <p>
+ * This NPN service provider negotiates using SPDY.
+ * <p>
+ * To enable NPN support, start the JVM with: {@code java -Xbootclasspath/p:<path_to_npn_boot_jar> ...}. The
+ * "path_to_npn_boot_jar" is the path on the file system for the NPN Boot Jar file which can be downloaded from Maven
+ * at coordinates org.mortbay.jetty.npn:npn-boot. Different versions applies to different OpenJDK versions.
+ *
+ * @see http://www.eclipse.org/jetty/documentation/current/npn-chapter.html
+ */
+public class SpdyClientProvider implements ClientProvider {
+
+    private String selectedProtocol;
+
+    @Override
+    public String selectProtocol(List<String> protocols) {
+        if (protocols.contains(SPDY_3_1.protocolName())) {
+            return SPDY_3_1.protocolName();
+        }
+        return selectedProtocol;
+    }
+
+    @Override
+    public boolean supports() {
+        return true;
+    }
+
+    @Override
+    public void unsupported() {
+        this.selectedProtocol = HTTP_1_1.protocolName();
+    }
+}

example/src/main/java/io/netty/example/spdyclient/SpdyClientStreamIdHandler.java

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+/*
+ * Copyright 2014 The Netty Project
+ *
+ * The Netty Project licenses this file to you under the Apache License,
+ * version 2.0 (the "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at:
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ */
+package io.netty.example.spdyclient;
+
+import io.netty.channel.ChannelHandlerAdapter;
+import io.netty.channel.ChannelHandlerContext;
+import io.netty.channel.ChannelPromise;
+import io.netty.handler.codec.http.HttpMessage;
+import io.netty.handler.codec.spdy.SpdyHttpHeaders;
+
+/**
+ * Adds a unique client stream ID to the SPDY header. Client stream IDs MUST be odd.
+ */
+public class SpdyClientStreamIdHandler extends ChannelHandlerAdapter {
+
+    private int currentStreamId = 1;
+
+    public boolean acceptOutboundMessage(Object msg) throws Exception {
+        return msg instanceof HttpMessage;
+    }
+
+    @Override
+    public void write(ChannelHandlerContext ctx, Object msg, ChannelPromise promise) throws Exception {
+        if (acceptOutboundMessage(msg)) {
+            HttpMessage httpMsg = (HttpMessage) msg;
+            if (!httpMsg.headers().contains(SpdyHttpHeaders.Names.STREAM_ID)) {
+                SpdyHttpHeaders.setStreamId(httpMsg, this.currentStreamId);
+                // Client stream IDs are always odd
+                currentStreamId += 2;
+            }
+        }
+        super.write(ctx, msg, promise);
+    }
+}

example/src/main/java/io/netty/example/spdyclient/SpdyFrameLogger.java

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+/*
+ * Copyright 2014 The Netty Project
+ *
+ * The Netty Project licenses this file to you under the Apache License,
+ * version 2.0 (the "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at:
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ */
+package io.netty.example.spdyclient;
+
+import io.netty.channel.ChannelHandlerAdapter;
+import io.netty.channel.ChannelHandlerContext;
+import io.netty.channel.ChannelPromise;
+import io.netty.handler.codec.spdy.SpdyFrame;
+import io.netty.util.internal.logging.InternalLogLevel;
+import io.netty.util.internal.logging.InternalLogger;
+import io.netty.util.internal.logging.InternalLoggerFactory;
+
+/**
+ * Logs SPDY frames for debugging purposes.
+ */
+public class SpdyFrameLogger extends ChannelHandlerAdapter {
+
+    private enum Direction {
+        INBOUND, OUTBOUND
+    }
+
+    protected final InternalLogger logger;
+    private final InternalLogLevel level;
+
+    public SpdyFrameLogger(InternalLogLevel level) {
+        if (level == null) {
+            throw new NullPointerException("level");
+        }
+
+        this.logger = InternalLoggerFactory.getInstance(getClass());
+        this.level = level;
+    }
+
+    @Override
+    public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
+        if (acceptMessage(msg)) {
+            log((SpdyFrame) msg, Direction.INBOUND);
+        }
+        super.channelRead(ctx, msg);
+    }
+
+    @Override
+    public void write(ChannelHandlerContext ctx, Object msg, ChannelPromise promise) throws Exception {
+        if (acceptMessage(msg)) {
+            log((SpdyFrame) msg, Direction.OUTBOUND);
+        }
+        super.write(ctx, msg, promise);
+    }
+
+    private boolean acceptMessage(Object msg) throws Exception {
+        return msg instanceof SpdyFrame;
+    }
+
+    private void log(SpdyFrame msg, Direction d) {
+        if (logger.isEnabled(this.level)) {
+            StringBuilder b = new StringBuilder("\n----------------").append(d.name()).append("--------------------\n");
+            b.append(msg.toString());
+            b.append("\n------------------------------------");
+            logger.log(this.level, b.toString());
+        }
+    }
+}

example/src/main/java/io/netty/example/spdyclient/package-info.java

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+/*
+ * Copyright 2014 The Netty Project
+ *
+ * The Netty Project licenses this file to you under the Apache License,
+ * version 2.0 (the "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at:
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ */
+
+/**
+ * This package contains an example SPDY HTTP client. It will behave like a SPDY-enabled browser and you can see the
+ * SPDY frames flowing in and out using the {@link io.netty.example.spdyclient.SpdyFrameLogger}.
+ *
+ * <p>
+ * This package relies on the Jetty project's implementation of the Transport Layer Security (TLS) extension for Next
+ * Protocol Negotiation (NPN) for OpenJDK 7 is required. NPN allows the application layer to negotiate which
+ * protocol, SPDY or HTTP, to use.
+ * <p>
+ * To start, run {@link io.netty.example.spdy.SpdyServer} with the JVM parameter:
+ * {@code java -Xbootclasspath/p:<path_to_npn_boot_jar> ...}.
+ * The "path_to_npn_boot_jar" is the path on the file system for the NPN Boot Jar file which can be downloaded from
+ * Maven at coordinates org.mortbay.jetty.npn:npn-boot. Different versions applies to different OpenJDK versions.
+ * See {@link http://www.eclipse.org/jetty/documentation/current/npn-chapter.html Jetty docs} for more information.
+ * <p>
+ * After that, you can run {@link io.netty.example.spdyclient.SpdyClient}, also settings the JVM parameter
+ * mentioned above.
+ */
+package io.netty.example.spdyclient;
+